The development and use of microbial agents as alternatives to chemicals for controlling noxious insect population has attracted increased attention and interest in recent years because of the public's increased awareness in maintaining the quality of the environment. The accumulation of pesticide residues in air, soil, water, and animals has helped to bring this heightened interest about. The insect pathogens in the family Baculoviridae, by virtue of their specificity, virulence, and safety for non-target species, have become logical candidates in this regard.
Several baculoviruses have been registered with the United States Environmental Protection Agency for use in the United States. Of the baculovirus products registered by the EPA, at least one, Elcar, the Heliothis zea nucleopolyhedrosis virus, was commercialized by Sandoz. Others which are registered for use under the auspices of the USDA Forest Service include Gypchek for control of the gypsy moth, Lymantria dispar, and TM-Bicontrol-1, for use against the Douglas-fir tussock moth, Orgyia pseudotsugata. A baculovirus product, Neochek S, has been used in Europe for control of the European pine sawfly, Neodiprion sertifer.
The development of viral insecticides has been patterned after conventional pesticidal use and technology, and this, in turn, has led in part at least to less than expected results when viral insecticides are used as substitutes for chemical pesticides. There are many factors to consider for effective use of insecticides; the size and age of the insect population, the time of day, and the means of application. There is also an education problem. Farmers like to see insects die immediately after treatment, and unmodified baculovirus insecticides usually take 5-7 days to kill. Failure to bring pest population below the economic threshold along with lack of quickness of kill are two of the main deficiencies of viral pesticides.